Metal foil having bumps, circuit substrate having the metal foil, and semiconductor device having the circuit substrate

ABSTRACT

A semiconductor device characterized in that: a circuit substrate of a single or multiple layer which is composed in such a manner that, bumps, which are electrically connected to connection electrodes provided on one face of a surface mount device, are arranged in the same plane arrangement as that of said connection electrodes and protruded onto one side of a sheet of metal foil, on which wiring patterns electrically connected to said bumps with each other are formed, and an insulating adhesive agent layer is made to adhere onto the one side of a sheet of metal foil having bumps, is made to adhere onto one face of the surface mount device by said insulating adhesive agent layer; and tips of the bumps respectively come into contact with the connection electrodes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a sheet of metal foil having bumps, acircuit substrate having the sheet of metal foil, and a semiconductordevice having the circuit substrate which are used for manufacturing asemiconductor chip.

2. Description of the Related Art

A chip size package is a semiconductor device, the size of which issubstantially the same as that of a semiconductor chip. Therefore, thechip size package is characterized in that the mount area can beremarkably reduced. In this chip size package, it is necessary toprovide an arrangement by which thermal stress generated between themount substrate and the semiconductor chip is reduced. Accordingly,various arrangements to reduce the thermal stress have been proposed.

Electrode terminals of the semiconductor chip are very fine and arrangedvery densely. On the other hand, external connection terminals such assolder balls are larger than the electrode terminals. Therefore, it isnecessary to arrange the external connection terminals in such a mannerthat the arranging intervals of the external connection terminals arelonger than those of the electrode terminals, and the externalconnection terminals are usually arranged on the overall electrodeterminal carrying surface in the formation of an area array.

FIG. 22 is a view showing an example of the arrangement of the electrodeterminals 12 of the semiconductor chips 10 and also showing an exampleof the arrangement of the lands 14 to which the external connectionterminals such as solder balls are joined. The lands 14 are arranged insuch a manner that the arranging intervals of the lands 14 are longerthan those of the electrode terminals 12, and the electrode terminals 12and the lands 14 are electrically connected with each other by thewiring sections 16.

When the land 14 is connected to the external connection terminal, it iscommon to adopt an arrangement having a cushioning function which iscomposed in such a manner that, for example, a metal post is verticallyattached onto the land 14 and the external connection terminal is joinedto an upper end portion of the metal post. Also, the followingarrangement is adopted. On an electrode terminal carrying surface of thesemiconductor chip, there is provided a buffer layer for reducingthermal stress, and a land of the wiring pattern film, which has beenmade to adhere via the buffer layer, is joined to the externalconnection terminal such as a solder ball, so that the cushioningfunction can be provided.

In the case of a circuit substrate on which a flip chip type ofsemiconductor chip is mounted, or in the case of a mount substrate onwhich a surface mount device such as a chip size package is mounted, theconnection electrodes such as solder bumps are very densely arranged.Therefore, it is impossible to electrically connect all the connectionelectrodes to the wiring patterns when the wiring layer is formed into asingle layer. For the above reasons, the wiring patterns are formed intoa multiple layers in the above cases.

In order to form the circuit substrate into a multiple layers, there isprovided a buildup method in which wiring patterns, which are interposedbetween insulating layers, are electrically connected with each otherwhile the insulating layers are being successively laminated so that amultiple layer can be formed. Also, there is provided a method in whicha multilayer of circuit substrates, on which the vias and the wiringpattern are previously formed, are laminated on each other so that amultiple layer can be formed.

In this connection, in order to manufacture a semiconductor devicehaving a fine pattern such as a chip size package, it is necessary toconduct machining with high accuracy.

For example, in the case where wiring is conducted on the electrodeterminal carrying surface of the semiconductor chip so as to form theconnection electrode having a predetermined pattern and an externalconnection terminal is joined to the connection electrode, it isnecessary to conduct fine machining in which metal posts for supportingthe external connection terminals are formed. In the case where aninsulating layer having a wiring pattern, which is also used as a bufferlayer, is formed on the electrode terminal carrying surface of thesemiconductor chip, it is necessary to provide a wire bonding process ora lead bonding process for electrically connecting the electrodeterminals of the semiconductor chip with the wiring patterns.

SUMMARY OF THE INVENTION

The present invention has been accomplished to solve the above problemscaused when the surface mount devices such as a semiconductor chip and achip size package are mounted. It is an object of the present inventionto provide a sheet of metal foil having bumps, a circuit substratehaving the sheet of metal foil, and a semiconductor device having thecircuit substrate capable of easily obtaining a mount structure in whichthe external connection terminals and the connection electrodes can beelectrically connected with each other even when the external connectionterminals, which are electrically connected to the electrode terminals,are formed on the electrode terminal carrying surface of thesemiconductor chip.

In order to accomplish the above object, the present invention iscomposed as follows.

The present invention provides a sheet of metal foil having bumpscharacterized in that: bumps, which are electrically connected toconnection electrodes provided on one face of a surface mount devicesuch as a semiconductor chip or a chip size package, are arranged in thesame plane arrangement as that of said connection electrodes, andprotruded onto one side of said sheet of metal foil.

Also, the present invention provides a sheet of metal foil having bumps,wherein lands to which the external connection terminals are joined,which respectively correspond to the bumps, are formed on the other sideof said sheet of metal foil.

Also, the present invention provides a sheet of metal foil having bumps,wherein wiring patterns are formed for electrically connecting the bumpsto the lands with each other, to which the external connection terminalsare joined, and are supported on supporters which couple adjacent wiringpatterns.

Also, the present invention provides a sheet of metal foil having bumps,wherein the external connection terminals respectively corresponding tothe bumps are formed on the other side of said sheet of metal foil beingprotruded.

Also, the present invention provides a sheet of metal foil having bumps,wherein wiring patterns are formed for electrically connecting the bumpsto the external connection terminals with each other, and are supportedon supporters which couple adjacent wiring patterns.

Also, the present invention provides a sheet of metal foil having bumps,wherein the external connection terminals are made of conductivematerial different from that of said sheet of metal foil.

Also, the present invention provides a sheet of metal foil having bumps,wherein an insulating adhesive agent layer is formed on one side of saidsheet of metal foil.

Also, the present invention provides a sheet of metal foil having bumps,wherein tips of the bumps are protruded from a surface of the insulatingadhesive agent layer.

Also, the present invention provides a sheet of metal foil having bumps,wherein a carrier tape is made adhere onto the other side of said sheetof metal foil.

Also, the present invention provides a circuit substrate of a multiplelayer characterized in that: bumps, which are electrically connected toconnection electrodes provided on one face of a surface mount devicesuch as a semiconductor chip or a chip size package, are arranged in thesame plane arrangement as that of said connection electrodes andprotruded onto one side of the sheet of metal foil; on which wiringpatterns, which are electrically connected to the said bumps with eachother, are formed; and an insulating adhesive agent layer is made toadhere onto one face of the sheet of metal foil having bumps.

Also, the present invention provides a circuit substrate of a single ormultiple layer, wherein the wiring pattern is an island-shaped wiringpattern having a land to which an external connection terminal is joinedat a base portion of the bump.

Also, the present invention provides a circuit substrate of a single ormultiple layer, wherein the wiring pattern is a wiring pattern having aland to which the external connection terminal is joined on the otherend side of the bump.

Also, the present invention provides a circuit substrate of a single ormultiple layer characterized in that: bumps, which are electricallyconnected to connection electrodes provided on one face of a surfacemount device such as a semiconductor chip or a chip size package, arearranged in the same plane arrangement as that of said connectionelectrodes and protruded onto one side of the sheet of metal foil;external connection terminals respectively corresponding to said bumpsare protruded onto the other side of said sheet of metal foil; on whichwiring patterns are formed for electrically connecting the bumps to saidexternal connection terminals with each other; and an insulating layeris made to adhere onto said one side of the sheet of metal foil havingbumps.

Also, the present invention provides a circuit substrate of a single ormultiple layer, wherein the external connection terminals are made ofconductive material different from that of the sheet of metal foil.

Also, the present invention provides a circuit substrate of a single ormultiple layer, wherein the conductive material is made of conductivepaste.

Also, the present invention provides a circuit substrate of a single ormultiple layer, wherein tips of the bumps are protruded from a surfaceof the insulating adhesive agent layer.

Also, the present invention provides a semiconductor devicecharacterized in that: a circuit substrate of a single or multiple layerwhich is composed in such a manner that, bumps, which are electricallyconnected to connection electrodes provided on one face of a surfacemount device such as a semiconductor chip or a chip size package, arearranged in the same plane arrangement as that of said connectionelectrodes and protruded onto one side of the sheet of metal foil; onwhich wiring patterns, which are electrically connected to the saidbumps with each other, are formed; and an insulating adhesive agentlayer is made to adhere onto said one side of the sheet of metal foilhaving bumps, is made to adhere onto said one face of the surface mountdevice by said insulating adhesive agent layer; and tips of the bumpsrespectively come into contact with the connection electrodes.

Also, the present invention provides a semiconductor device, wherein thewiring pattern is an island-shaped wiring pattern having a land to whichthe external connection terminal is joined at a base portion of thebump.

Also, the present invention provides a semiconductor device, wherein thewiring pattern is a wiring pattern having a land to which the externalconnection terminal is joined on the other end side of the bumps.

Also, the present invention provides a semiconductor device, wherein theexternal connection terminals are joined to the lands.

Also, the present invention provides a semiconductor devicecharacterized in that: a circuit substrate of a single or multiple layerwhich is composed in such a manner that, bumps, which are electricallyconnected to connection electrodes provided on one face of a surfacemount device such as a semiconductor chip or a chip size package, arearranged in the same plane arrangement as that of said connectionelectrodes and protruded onto one side of the sheet of metal foil; onwhich wiring patterns are formed for electrically connecting said bumpsto external connection terminals with each other; which respectivelycorrespond to the bumps and are protruded onto the other side of thesheet of metal foil; and an insulating adhesive agent layer is made toadhere onto said one face of the sheet of metal foil having bumps, ismade to adhere onto said one face of the surface mount device by saidinsulating adhesive agent layer; and tips of the bumps respectively comeinto contact with the connection electrodes.

Also, the present invention provides a semiconductor device, wherein theoutside of the external connection terminals are plated with solder.

Also, the present invention provides a semiconductor device, wherein theexternal connection terminals are made of conductive material differentfrom that of the sheet of metal foil.

The sheet of metal foil having bumps, the circuit substrate having thesheet of metal foil, and the semiconductor device having the circuitsubstrate of the present invention can provide the following advantages.Even when the connection electrodes of the surface mount device such asa semiconductor chip or a chip size package are very densely arranged,it is possible to electrically connect the external connection terminalsto the connection electrodes without extending the mount area.

The present invention can also provide the following advantages. Sincebumps are formed on a sheet of metal foil by press working, the sheet ofmetal foil having the bumps according to the present invention can besuitably mass-produced, and the manufacturing cost can be reduced.Further, it is possible to easily make a circuit substrate having bumpsarranged very densely.

Also, the present invention can provide the following advantages. Thecircuit substrate according to the present invention, which has theadhesive agent layer provided on the sheet of metal foil having bumps,can be made to adhere onto the electrode terminal carrying surface ofthe semiconductor chip. Therefore, the semiconductor device can beeasily manufactured.

Further, the semiconductor device according to the present invention canbe easily manufactured. Furthermore, thermal stress generated by adifference of the coefficient of thermal expansion between the mountsubstrate and the semiconductor chip can be effectively reduced by theadhesive agent layer. Therefore, it is possible to conduct mounting veryreliably.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing an embodiment of thesemiconductor device.

FIG. 2 is a cross-sectional view showing another embodiment of thesemiconductor device.

FIG. 3 is a cross-sectional view showing still another embodiment of thesemiconductor device.

FIG. 4 is a cross-sectional view showing an embodiment of the sheet ofmetal foil having bumps.

FIG. 5 is a cross-sectional view showing another embodiment of the sheetof metal foil having bumps.

FIG. 6 is a cross-sectional view showing still another embodiment of thesheet of metal foil having bumps.

FIG. 7 is a cross-sectional view showing still another embodiment of thesheet of metal foil having bumps.

FIG. 8 is a plan view showing a plane arrangement of the bumps.

FIG. 9 is a plan view showing a plane arrangement of the bumps, landsand wiring patterns.

FIGS. 10(a 1) to 10(d 2) are perspective views and cross-sectional viewsshowing examples of the bumps.

FIGS. 11(a 1) to 11(d 2) are perspective views and cross-sectional viewsshowing another example of the bumps.

FIGS. 12(a 1) to 12(c) are perspective views and cross-sectional viewsshowing still another example of the bumps.

FIG. 13 is a cross-sectional view showing an embodiment of the circuitsubstrate.

FIG. 14 is a cross-sectional view showing another embodiment of thecircuit substrate.

FIG. 15 is a cross-sectional view showing still another embodiment ofthe circuit substrate.

FIG. 16 is a cross-sectional view showing still another embodiment ofthe circuit substrate.

FIG. 17 is a cross-sectional view showing still another embodiment ofthe circuit substrate.

FIG. 18 is a cross-sectional view showing an embodiment of themulti-layer circuit substrate.

FIGS. 19(a 1) to 19(c) are schematic illustrations showing a method ofmanufacturing the semiconductor device.

FIG. 20 is a cross-sectional view showing another embodiment of thesemiconductor device.

FIG. 21 is a cross-sectional view showing still another embodiment ofthe semiconductor device.

FIG. 22 is a schematic illustration showing an arrangement of theelectrode terminals and lands of the semiconductor chip.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the appended drawings, the preferred embodiments of thepresent invention will be explained in detail as follows.

Semiconductor Device

FIGS. 1 to 3 are cross-sectional views respectively showing anarrangement of the semiconductor device manufactured by using a sheet ofmetal foil 20 having bumps.

FIG. 1 is a cross-sectional view showing a semiconductor devicemanufactured in such a manner that the sheet of metal foil 20 havingbumps is made to adhere onto an electrode terminal carrying surface ofthe semiconductor chip 10 via the adhesive agent layer 18. This sheet ofmetal foil 20 having bumps used for the semiconductor device is composedin such a manner that the bumps 22 are formed on the sheet of metal foilin the same plane arrangement as that of the electrode terminals 12formed on the electrode terminal carrying surface. As shown in thedrawings, the sheet of metal foil 20 having bumps is made to adhere ontothe electrode terminal carrying surface of the semiconductor chip 10 viathe adhesive agent layer 18 under the condition that each forward endportion of the bump 22 comes into contact with each electrode terminal12.

On the sheet of metal foil 20, there are provided wiring patterns 26 forelectrically connecting each bump 22 to each external connectionterminal 24. The bump 22 is formed on one end side of the wiring pattern26, and the land 28 for joining the external connection terminal 24 isformed on the other end side of it. In the embodiment shown in FIG. 1,solder balls are used for the external connection terminals 24. Eachbump 22 is formed into a configuration, the size of which is minute, sothat the bump 22 can be connected to the electrode terminal 12. On theother hand, the land 28 is formed into a configuration, the size ofwhich is a predetermined value, so that the land 28 can be joined to anexternal connection terminal such as a solder ball.

In the above embodiment, the external surface of the sheet of metal foil20 having bumps is covered with the protective film 30 of solder resistso that only the lands 28 can be exposed.

When the semiconductor device shown in FIG. 1 is mounted on a mountsubstrate, the external connection terminal 24 is joined to a connectingsection of the circuit pattern provided on the mount substrate. Theadhesive agent layer 18 has a function of making the sheet of metal foil20 having bumps adhere to the semiconductor chip 10. Also, the adhesiveagent layer 18 has a function of reducing thermal stress generatedbetween the mount substrate and the semiconductor element 10.

In this connection, the semiconductor device may be composed in such amanner that the external connection terminal 24 is not joined to theland 28 but the land 28 is left being exposed and a connection bumpprovided on the mount substrate is joined to the land 28.

The semiconductor device shown in FIG. 2 is characterized in that boththe bumps 22 and the external connection terminals 23 are previouslyformed on the sheet of metal foil. On the sheet of metal foil 20 havingbumps, the protruding connection terminals 23 are formed by pressworking so that the protruding connection terminals 23 can agree withthe positions of the connecting portions of the wiring patterns providedon the mount substrate. Each bump 22 is electrically connected to eachconnection terminal 23, so that the wiring pattern 26 can be formed.

When the connection terminals 23 are formed being protruded as shown inFIG. 2, the semiconductor device can be manufactured by positioning andsoldering the connection terminals 23 and the connecting sections of themount substrate. In this connection, when the external faces of theconnection terminals 23 are previously plated with solder, mounting canbe easily carried out.

When the sheet of metal foil 20 having bumps, on which the protrudingconnection terminals 23 are formed as shown in FIG. 2, is used, it ispossible to provide an advantage that mounting can be carried outwithout using the external connection terminals 24 such as solder balls.When the bumps 22 and the connection terminals 23 are formed on thesheet of metal foil by press working, the sheet of metal foil 20 havingbumps can be manufactured at low cost.

FIG. 3 is a cross-sectional view showing still another embodiment of thesemiconductor device. In this embodiment, the wiring patterns are notdrawn around, and the lands 28 are provided in the same planearrangement as that of the electrode terminals 12 of the semiconductorchips 10, and the external connection terminals 24 are joined to thelands 28. A base portion of each bump 22 is formed into an independentisland-shape, and an external face of the base portion of the bump 22 isformed onto the land 28 to which the external connection terminal 24 isjoined. Also, in this embodiment, each wiring pattern 26 is composed ofthe bump 22 and the land 28.

On the external face of the base portion of the bump 22, there isprovided a recess which is formed when the bump 22 is formed into aprotruding shape. This recess is filled with solder when the externalconnection terminal 24 such as a solder ball is joined to the recess.Except for the lands 28, the external face of the sheet of metal foil 20having bumps is covered with a protective film 30 made of solder resist.

When the plane arrangement of the electrode terminals 12 and that of theexternal connection terminals 24 are made to be the same as shown inthis embodiment, the bump 22 can be formed into a minute configurationso that it can be connected to the electrode terminal 12, and on theother hand, the land 28 is provided with a necessary area so that it canbe joined to the external connection terminal 24. Therefore, the bump 22and the land 28 have a function of converting the size of the electrodeterminal 12 into the size of the external connection terminal 24. Theaforementioned function of converting the size of the electricalconnecting section is useful, because it becomes possible to connect alarger external connection terminal 24 to the land 28 in the samearrangement even when the electrode terminal 12 is formed into a minuteconfiguration. Since the adhesive agent layer 18 is interposed in thisembodiment, it is possible to reduce thermal stress generated in thecase of mounting.

In the semiconductor devices of the aforementioned embodiments shown inFIGS. 1 to 3, the bumps 22 on the sheet of metal foil are connected tothe electrode terminals 12 provided on the electrode terminal carryingsurface of the semiconductor chip 10. However, it is possible to adoptan arrangement in which the bumps 22 are connected to the connectionelectrodes formed by rewiring on the electrode terminal carrying surfaceof the semiconductor chip 10.

Rewiring is conducted in the case where the electrode terminals 12 arevery densely arranged, so that the bumps 22 can not be connected to theelectrode terminals 12 as they are. Also, rewiring is conducted in thecase where the connection electrodes for connecting the bumps 22 arearranged according to the arrangement of the external connectionterminals 24. In the case of the semiconductor chip 10 in which theconnection terminal is formed by rewiring on the electrode terminalcarrying surface, it is possible to provide a semiconductor devicecapable of being mounted when the sheet of metal foil 20 having bumps ismade to adhere by the adhesive agent layer 18 and the bumps 22 areconnected to the connection electrodes.

Sheet of Metal Foil Having Bumps

FIGS. 4 to 7 are views showing embodiments of the sheet of metal foilhaving bumps.

FIG. 4 is a view showing a sheet of metal foil 20, on one face 20 a ofwhich the bumps 22 are formed in the same arrangement as that of theelectrode terminals of the connection electrodes provided on the surfacemount device such as a semiconductor chip 10 or a chip size package.

On this sheet of metal foil 20 having bumps, the protruding bumps 22 areformed when a flat sheet of metal foil 20 a is subjected to pressworking. The method of forming the bumps 22 by press working isadvantageous in that a large number of bumps 22 can be effectivelyformed, so that the sheets of metal foil 20 having bumps can be easilymanufactured and mass-produced.

FIG. 8 is a view showing an example of the plane arrangement of thebumps 22 provided on the sheet of metal foil. The bumps 22 are formedaccording to the arrangement of the connection electrodes such as theelectrode terminals 12 formed on the electrode terminal carrying surfaceof the semiconductor chip 10. For example, when the electrode terminals12 are arranged in the shape of an area array, the bumps 22 are alsoarranged in the shape of an area array as shown in the drawing.

The configuration of each bump 22 formed on the sheet of metal foil maybe a configuration by which the bump 22 can be contacted with andelectrically connected to the connection electrode provided on surfacemount device such as a semiconductor chip or a chip size package.

FIG. 4 is a view showing an example of the sheet of metal foil 20 havingbumps which are formed conical. However, it is possible to form thebumps 22 into various configurations. FIGS. 10 to 12 are perspective andcross-sectional views of the bumps 22 formed on the sheet of metal foil.FIGS. 10(a 1) to 10(d 2) are views showing examples of theconfigurations of the bumps 22 which are formed into a cone, pyramid,hemisphere and column. FIGS. 11(a 1) to 11(d 2) are views showingconfigurations of the bumps 22 which are raised by cutting. In theseexamples, the side configurations are formed into a V-shape, U-shape,J-shape and L-shape. FIGS. 12(a 1) to 12(b 2) are views of theconfigurations of the bumps, the side configurations of which are formedby combining two J-shape components opposed to each other and also bycombining two sharp J-shape components opposed to each other. FIG. 12(c)is a view showing an example of the configuration of the bump which isformed into a spiral.

As shown in FIGS. 10(a 1) to 10(c 2), when the bump 22 is formed into acone, pyramid or hemisphere, the configuration of the bump 22 can bestably maintained, and the positional accuracy can be enhanced. The bump22 having a top in the configuration, such as the conical bump 22, issuperior to the columnar bump 22 shown in FIGS. 10(d 1) and 10(d 2),because it is possible for the bump 22 having the top to conductelectrical connection by point contact, so that the connectionelectrodes can be very densely arranged, that is, the bump 22 having thetop, including such as the conical bump 22, can be easily joined to theconnection electrode. In this connection, in the examples shown in FIGS.10(a 1) to 10(d 2), it is possible to form a through-hole at the top ofthe bump 22.

When the bumps 22 are formed by being raised by cutting as shown inFIGS. 11 and 12, the sides of the bumps 22 are open. Especially, in thecases shown in FIGS. 11(c 1) and 1lc 2) and also shown in FIGS. 11(d 1)and 11(d 2), in which the bumps 22 are formed into a J-shape, L-shape orsharp J-shape and one of the base portions supporting the bump 22 isseparate from the sheet of metal foil, elasticity is given to the bump22. Due to the elasticity of the bump 22, thermal stress generated inthe process of mounting on a mount substrate can be reduced by the bump22. In the case of the spiral bump 22 shown in FIG. 12(c), theelasticity and cushioning function of the bump 22 can be furtherenhanced, and thermal stress can be more effectively reduced.

The sheet of metal foil 20 having bumps can be made of metal such ascopper, aluminum, gold, silver or stainless steel. When the bumps 22 areformed on the sheet of metal foil 20 a by press working, the prior artof press working in which a die and punch are used can be applied. Whena metal sheet is subjected to press working, it is possible to provide avery high accuracy of forming. Therefore, minute bumps 22 can be easilyformed according to the arrangement of the connection electrodes. Inthis connection, in the case where the bumps 22 are formed on the sheetof metal foil 20 a, it is possible to form the bumps 22 of the sameconfiguration on the overall sheet of metal foil 20 a. It is alsopossible to form bumps 22 of different configurations which are arrangedon the sheet of metal foil 20 a being mixed with each other.

FIG. 5 is a view showing a sheet of metal foil 20 having both the bumps22 and the connection terminals 23 used as external connectionterminals. That is, on the sheet of metal foil 20 a, the bumps 22 andthe connection terminals 23 are formed by press working. Since theconnection terminals 23 are used as external connection terminals, theyare formed being protruded onto the opposite side to the side on whichthe bumps 22 are formed on the sheet of metal foil 20 a. As shown inFIGS. 10 to 12, the connection terminals 23 may be formed into variousconfigurations. However, since the connection terminals 23 are connectedto the connecting sections of the mount substrate by solder, it ispreferable that the configuration of each connection terminal 23 isformed so that a predetermined joining area can be ensured.

In this connection, instead of forming the connection terminals 23 bypress working, a conductor having bumps, which is different from thesheet of metal foil 20 a, may be formed on the face of the sheet ofmetal foil 20 a onto which the external connection terminals areconnected, so that the conductor can be used as the connection terminals23. Examples of the methods of forming the connection terminals 23 bythe different conductor are: a method in which the connection terminalsare made to swell by plating; and a method in which the connectionterminals are formed into bumps by printing or transferring conductorpaste.

When the above sheet of metal foil 20 having bumps provided with theexternal connection terminals 23 is used, it becomes unnecessary to jointhe external connection terminals such as solder balls in the laterprocess.

The sheet of metal foil 20 shown in FIGS. 6 and 7 is characterized inthat the wiring patterns 26 for electrically connecting the bumps 22with the external connection terminals are formed. FIG. 9 is a viewshowing the wiring patterns 26 including the bumps 26 and the lands 28.Each wiring pattern 26 is formed being drawn around on a plane so thatthe bump 22 and the land 28, to which the external terminal is joined,can be electrically connected with each other. In order to independentlyform the bump 22, the land 28 and the wiring pattern 26 for connectingthem, it is preferable that the wiring pattern 26 is supported by thecarrier tape 32 capable of being peeled off from the sheet of metal foil20 a as shown in FIG. 6.

FIG. 7 is a view showing a sheet of metal foil 20 having bumps on whichthe wiring patterns 26 for connecting the bumps 22 to the connectionterminals 23 are formed. In the case of this sheet of metal foil 20having bumps, the wiring patterns 26 can be connected to and supportedby the support frame without using the above carrier tape 32.

In this connection, in the case where the bumps 22 are formed by pressworking on the sheet of metal foil 20 a , it is possible to form thebumps 22 after the sheet of metal foil 20 a has been patterned.

Circuit Substrate

As shown in FIGS. 1 to 3, the sheet of metal foil 20 having bumps can beattached onto the electrode terminal carrying surface of thesemiconductor chip 10 or the electrode terminal carrying surface of thesurface mount device such as a chip size package. In this way, the sheetof metal foil 20 having bumps can be used for composing a predeterminedmount structure of the semiconductor device.

When the sheet of metal foil 20 having bumps is attached to theelectronic device such as a semiconductor chip 10 as described above, itis attached via the adhesive agent layer 18. Therefore, it is effectiveto previously provide the adhesive agent layer 18 on the sheet of metalfoil 20 having bumps.

FIGS. 13 to 16 are views showing examples of the sheet of metal foil 20having bumps on which the adhesive agent layer 18 is provided.

FIG. 13 is a view showing the sheet of metal foil 20 having bumps, onone face of the sheet of metal foil 20 a of which the protruding bumps22 are formed and the adhesive agent layer 18 is provided. In this case,the adhesive agent layer 18 is provided so that all of the one face ofthe sheet of metal foil 20 having bumps can be covered with the adhesiveagent layer 18. In this connection, in the case where one face of thesheet of metal foil 20 having bumps on which the bumps 22 are formed iscovered with the adhesive agent layer 18 and the tip portions of thebumps 22 are protruded from the surface of the adhesive agent layer 18,the following two cases may be encountered. One is a case in which thetip portions of the bumps 22 and the surface of the adhesive agent layer18 are made to be on the same face, and the surfaces of the bump 22 areexposed from the surface of the adhesive agent layer 18. The other is acase, the tip portions of the bumps 22 are embedded in the adhesiveagent layer 18.

In the case where the tip portions of the bumps 22 are protruded orexposed from the adhesive agent layer 18, the sheet of metal foil 20having bumps can be electrically connected to the connection electrodessuch as the electrode terminals 12 provided in the electronic part suchas the semiconductor chip 10 as they are.

Even if the bumps 22 are embedded in the adhesive agent layer 18, whenthe sheet of metal foil 20 having bumps is made to adhere onto theadhesive face while they are being strongly pressed against the adhesiveface, the tip portions of the bumps 22 can be protruded from theadhesive agent layer 18, so that the tip portions of the bumps 22 can bepressed against the connection electrodes such as the electrodeterminals 12. In this way, the electrical connection can beaccomplished.

FIG. 14 is a view showing an embodiment of the sheet of metal foil 20having bumps on which the bumps 22 and the connection terminals 23 areprovided, and the adhesive agent layer 18 is provided on the face of thesheet of metal foil 20 on which the bumps 22 are formed.

FIG. 15 is a view showing a circuit substrate 40 which has the adhesiveagent layer 18 covering the bump carrying face of the sheet of metalfoil 20 having bumps on which the wiring patterns 26 are formed.

FIG. 16 is a view showing a circuit substrate 40 which has the adhesiveagent layer 18 provided on the sheet of metal foil 20 having bumps onwhich the bumps 22, the connection terminals 23 and the wiring patterns26 for electrically connecting them are formed. When the wiring patterns26 are formed, the wiring patterns for electrically connecting the bumps22 to the connection terminals 23 can be used as signal patterns, groundpatterns or power supply patterns.

In this connection, in this specification, the circuit substrate 40 isdefined as a sheet of metal foil 20 having bumps provided with theadhesive agent layer 18 on which the wiring patterns 26 are formed onthe sheet of metal foil 20 a. Also, in this specification, the sheet ofmetal foil having bumps is defined as a sheet of metal foil 20 havingbumps in which only bumps 22 are formed on the sheet of metal foil 20 aand no wiring patterns 26 are formed.

Concerning the form of the sheet of metal foil 20 having bumps providedwith the adhesive agent layer 18 and also concerning the form of thecircuit substrate 40, it is possible to adopt various forms as describedbefore according to the configurations of bumps 22 provided on the sheetof metal foil 20 having bumps, the configurations of the connectionterminals 23, and/or the wiring patterns 26. As long as a predeterminedadhesion function can be provided by the adhesive agent layer 18adhering to the sheet of metal foil 20 having bumps, any adhesive agentlayer 18 may be adopted. Either thermosetting resin or thermoplasticresin may be used, that is, the material is not particularly restricted.

As shown by the embodiments illustrated in FIGS. 13 and 14, the sheet ofmetal foil 20 having bumps and the circuit substrate 40 may be providedin such a manner that all face on the mount face side is exposed.Alternatively, as shown by the embodiments illustrated in FIGS. 15 and16, the sheet of metal foil 20 having bumps and the circuit substrate 40may be provided in such a manner that the mount face side is coveredwith the protective film 30 made of solder resist. In the case where themount face side of the circuit substrate 40 is covered with theprotective film 30, the lands 28 to which the external connectionterminals are joined are exposed, or the connection end portions of theconnection terminals 23 are exposed.

On the circuit substrate 40, it is preferable that the connection endportions of the lands 28 with the connection terminals 23 are plated bynickel-gold alloy so that the connection end portions can be excellentlyjoined to the external connection terminals. In the case of plating bynickel-gold alloy, the mount face side of the sheet of metal foil 20 amay be covered with the protective layer 30 made of solder resist, andelectrolytic plating may be conducted under this condition.

On the sheet of metal foil 20 having bumps provided with the adhesiveagent layer 18 and also on the circuit substrate 40, the tip portions ofthe bumps 22 exposed onto the surface of the adhesive agent layer 18 maybe subjected to plating of gold, tin, lead or silver, or alternativelythe tip portions of the bumps 22 exposed onto the surface of theadhesive agent layer 18 may be coated with conductive material such assilver paste, so that the tip portions of the exposed bumps 22 can beelectrically connected with the connection electrodes provided in theelectronic part such as a semiconductor chip.

Method of manufacturing the circuit substrate and others

Methods of manufacturing the above circuit substrate 40 and the sheet ofmetal foil 20 having bumps provided with the adhesive agent layer 18 aredivided into two main methods. One is a method in which, before apredetermined wiring pattern is formed on the sheet of metal foil 20 a,one face, on which the bumps are formed, of the sheet of metal foil 20 ais covered with the adhesive agent layer 18. The other is a method inwhich, after a predetermined wiring pattern has been formed on the sheetof metal foil 20 a, one face of the sheet of metal foil 20 a is coveredwith the adhesive agent layer 18.

The method in which one face, on which the bumps are formed, of thesheet of metal foil 20 a is covered with the adhesive agent layer 18before a predetermined wiring pattern is formed on the sheet of metalfoil 20 a, is divided into the following two methods (1) and (2).

Method (1) is described as follows. The sheet of metal foil 20 a issubjected to press working so as to form the bumps 22. After that, theface on which the bumps 22 have been formed are covered with theadhesive agent layer 18. Then, the wiring patterns are formed.

On the sheet of metal foil 20 having bumps provided with the adhesiveagent layer shown in FIG. 13, when the sheet of metal foil 20 a isetched, it is possible to obtain the circuit substrate 40 having thewiring pattern 26 shown in FIG. 17. Since the sheet of metal foil 20 ais supported by the adhesive agent layer 18, it is possible to form anarbitrary wiring pattern.

The sheet of metal foil 20 having bumps shown in FIG. 13, on which thewiring patterns have not been formed yet, can be made by the followingmethods. One is a method in which liquid of insulating resin, whichbecomes the adhesive agent layer 18, is coated on the sheet of metalfoil 20 a on which the bumps 22 are formed. The other is a method inwhich an adhesive agent sheet having a function of adhesion is made toadhere.

As described above, the tip portions of the bumps 22 are exposed ontothe surface of the adhesive agent layer 18 or embedded in the adhesiveagent layer 18. In order to expose the tip portions of the bumps 22 fromthe surface of the adhesive agent layer 18, after liquid resin is coatedon the surface of the sheet of metal foil 20 a, or alternatively afterthe adhesive agent sheet is made to adhere, a pressing jig having a flatface is pressed on the adhesive agent layer 18 in the thicknessdirection of it, so that the tip portions of the bumps 22 can be exposedonto the surface of the adhesive agent layer 18. If the pressing jig ismade of material having a cushioning function and also if the surface ofthe pressing jig for pressing the adhesive agent layer 18 is made to beseparable, it becomes possible to protrude the tip portions of the bumps22 from the surface of the adhesive agent layer 18. In this connection,when pressing is conducted by the pressing jig, the adhesive agent layer18 may be heated a little so as to ensure the configuration.

Method (2) is described as follows. After the adhesive agent layer 18has been made to adhere onto one face of the sheet of metal foil 20 a,the bumps 22 are formed, and then the wiring patterns are formed.

According to this method, when the bumps 22 are formed by press workingon the sheet of metal foil 20 a, the bumps 22 are formed via theadhesive agent layer 18.

At this time, simultaneously when the bumps 22 are formed, the tipportions of the bumps 22 are exposed from the adhesive agent layer 18.

In this connection, when the sheet of metal foil 20 a is subjected topress forming, it is possible to form a predetermined wiring patternbefore the bumps 22 are formed. Since the sheet of metal foil 20 a issupported by the adhesive agent layer 18, the predetermined wiringpattern may be formed on the sheet of metal foil 20 a either before orafter the bumps 22 are formed.

After the predetermined wiring pattern has been formed on the sheet ofmetal foil 20 a, one face of the sheet of metal foil 20 a is coveredwith the adhesive agent layer 18. In this case, the following methods(3) to (5) are provided.

Method (3) is described as follows. After the predetermined wiringpatterns have been formed on the sheet of metal foil 20 a and the bumps22 have been formed, the bump carrying face is covered with the adhesiveagent layer 18. According to this method, the predetermined wiringpatterns are formed on the sheet of metal foil 20 a under the conditionthat the adhesive agent layer 18 has not been formed. Therefore, it isnecessary to form the wiring pattern while the sheet of metal foil 20 ais being supported by the frame. After the wiring patterns 26, theconfigurations of which are established by themselves, have been formedas described above, liquid of insulating resin is coated on the bumpcarrying face, or alternatively an adhesive agent sheet is made toadhere, so that the adhesive agent layer 18 is provided. In thisconnection, the order of the process in which the predetermined wiringpattern is formed on the sheet of metal foil 20 a and the process offorming the bumps 22 can be changed. Accordingly, it is possible to formthe predetermined wiring patterns after the bumps 22 have been formed.

Method (4) is described as follows. After the predetermined wiringpatterns have been formed on the sheet of metal foil 20 a, one face ofthe sheet of metal foil 20 a is covered with the adhesive agent layer18, and press working is conducted on the sheet of metal foil 20 a ontowhich the adhesive agent layer 18 is attached, so that the bumps 22 canbe formed. According to this method, the predetermined wiring patternsare formed before the sheet of metal foil 20 a is supported by theadhesive agent layer 18. Therefore the wiring patterns, which areadjacent to each other, must be connected to with each other by asupport piece.

Since the adhesive agent layer 18 is attached onto the sheet of metalfoil 20 a, the sheet of metal foil 20 a is subjected to press workingvia the adhesive agent layer 18, so that the bumps 22 can be formed. Atthis time, the tip portions of the bumps 22 are exposed or embedded inthe adhesive agent layer 18.

In this connection, in the case where the predetermined wiring patternsare formed on the sheet of metal foil 20 a before the sheet of metalfoil 20 a is supported by the adhesive agent layer 18 as describedabove, the wiring patterns, which are adjacent to each other, must beconnected to with each other by a support piece. However, when the sheetof metal foil 20 a is previously supported by the carrier tape 32, itbecomes possible to form arbitrary wiring patterns on the sheet of metalfoil 20 a.

Method (5) is described as follows. The carrier tape 32 is made toadhere onto a face of the sheet of metal foil 20 a opposite to the faceon which the bumps 22 are formed, so that the sheet of metal foil 20 acan be supported. Under the above condition, the predetermined patternsare formed on the sheet of metal foil 20 a, or alternatively pressworking is conducted.

In the method of supporting the sheet of metal foil 20 a by the carriertape 32, either the formation of predetermined patterns on the sheet ofmetal foil 20 a or the press working may be conducted first. That is,after the wiring patterns 26 and the bumps 22 have been formed byforming the predetermined patterns on the sheet of metal foil 20 a andconducting press working, the adhesive agent layer 18 is made to adhereonto the face on which the bumps 22 are formed.

As an alternative method, the predetermined wiring patterns are formedon the sheet of metal foil 20 a under the condition that the sheet ofmetal foil 20 a is supported by the carrier tape 32, and the adhesiveagent layer 18 is provided on one face of the sheet of metal foil 20 a,and then the bumps 22 are formed by press working.

The carrier tape 32 is provided for supporting the sheet of metal foil20 a. Therefore, the carrier tape 32 is selected so that it can beeasily peeled off from the sheet of metal foil 20 a. In the case ofmounting, the carrier tape 32 is peeled off from the circuit substrate40. In this connection, it is possible to adopt an arrangement in whichthe carrier tape 32 is made to adhere onto the face on which theadhesive agent layer 18 is provided or the mount face of the sheet ofmetal foil 20 a in such a manner that the carrier tape 32 is separableso that it can be used for protecting the circuit substrate.

Multilayer Circuit Substrate

All of the aforementioned circuit substrates are composed of a singlelayer. However, it is possible to provide a multilayer circuit substrateby laminating circuit substrates 40 on which the adhesive agent layers18 are provided on the faces on which the bumps 22 are formed.

FIG. 18 is a view showing an embodiment of the multilayer circuitsubstrate. The circuit substrates 40 having the same wiring patterns 26as those of the circuit substrate shown in FIG. 17 are laminated andadhere to each other by the adhesive agent layers 18, so that themultilayer circuit substrate can be obtained.

The bumps 22 formed on the circuit substrate 40 function as vias forelectrically connecting the wiring patterns 26 between the layers, andwhen the wiring patterns 26 and the bumps 22 on the layers areappropriately arranged, it is possible to obtain a multilayer circuitsubstrate having a predetermined electrical connection pattern.

In the case where the circuit substrates 40 are laminated so as to forma multiple layer, it is common that the tip portions of the bumps 22 onthe lower layer come into contact to the lower face of the wiringpatterns 26 on the upper layer. However, depending upon a case, thebumps 22 on the lower layer and the bumps 22 on the upper layer may belocated at the same positions on a plane. When there is a possibilitythat an electrical connection can not be positively accomplished betweenthe layers because of recesses formed at the bottom portions of thebumps 22 on the upper layer, the recesses of the bumps 22 may be filledwith conductive material so as to ensure the electrical connection.

When the circuit substrate 40 having a multiple layer is provided, it ispossible to accomplish various arrangements which can not be provided bythe circuit substrate of a single layer. For example, it is possible toprovide a ground layer or a power supply layer on the circuit substrate.

Concerning the configurations of the bumps 22 provided on the circuitsubstrate 40 laminated into a multiple layer, it is possible to usevarious forms combined with each other as shown in FIGS. 10, 11 and 12.

Method of Manufacturing Semiconductor Devices

The adhesive agent layer 18 is previously formed on the above circuitsubstrate 40 of a single or multiple layer, and the bumps 22 are formedaccording to the arrangement of the connection electrodes provided inthe electronic device such as a semiconductor chip or a chip sizepackage. Therefore, when the semiconductor device is manufactured, theelectrode terminal carrying surfaces of the semiconductor chip 10 andthe bumps 22 of the circuit substrate 40 are positioned so as to agreewith each other and made to adhere by the adhesive agent layer 18. Dueto the foregoing, the bumps 22 and the electrode terminals 12 can beelectrically connected to with each other. In this way, it is possibleto manufacture a semiconductor device having the wiring patterns 26 usedfor external connection and the lands 28 on the electrode terminalcarrying surfaces.

FIGS. 19(a 1) to 19(c) are views showing a method by which thesemiconductor device 50 is formed by making the circuit substrate 40adhere to the semiconductor chip 10. The semiconductor chip 10 and thecircuit substrate 40 are positioned with each other as shown in FIGS.19(a 1) and 19(a 2), and the circuit substrate 40 is made to adhere tothe semiconductor chip 10 as shown in FIG. 19(b). Then, the externalconnection terminals 24 such as solder balls are joined to the lands 28.In this way, the semiconductor device 50 can be made as shown in FIG.19(c).

In this connection, it is possible to use the semiconductor device 50while the external connection terminals 24 are not joined. In the caseof the circuit substrate 40 provided with the connection terminals 23,it is possible to use it as the semiconductor device 50 as it is. Also,in the case of the circuit substrate 40 provided with the connectionterminals 23, solder bumps may be attached to the connection terminals23.

The semiconductor device 50 is not limited to the face-down type shownin FIG. 19, but it is possible to adopt the face-up type shown in FIG.20. Reference numeral 42 is a lead extending from the periphery of theelectrode terminal carrying surface of the semiconductor chip 10. Thelead 42 is bent so that it can be connected with the connecting sectionof the mount substrate.

FIG. 21 is a view showing a semiconductor device in which twosemiconductor chips 10 are laminated on each other by using a multilayercircuit substrate. Electrode terminal carrying surfaces of thesemiconductor elements 10, 10 are opposed to each other, and theadhesive agent layers 18 of the multilayer circuit substrate are made toadhere onto the electrode terminal carrying surfaces of thesemiconductor chips 10, 10. Due to the foregoing, it is possible toobtain a semiconductor device in which the electrode terminals 12 of thesemiconductor chips 10, 10 are electrically connected to the lead 42.

What is claimed is:
 1. A circuit substrate composed of multiple layers characterized in that the first layer comprises bumps, which are electrically connected to connection electrodes and a bottom surface of a foil wiring pattern provided on one face of a surface mount device which is a semiconductor chip or a chip size package, wherein said bumps are arranged in the same plane arrangement as that of said connection electrodes and protrude from one side of the sheet of metal foil; and the other layers comprise a plurality of wiring patterns, one in each of the plurality of layers, which comprise bumps and are electrically connected via said bumps to each other or to the wiring pattern in the first layer; and an insulating adhesive agent layer adhering to each of said sheet of metal foil wiring patterns having bumps.
 2. A circuit substrate of multiple layers according to claim 1, wherein the wiring pattern is an island-shaped wiring pattern having a land to which an external connection terminal is Joined at a base portion of the bumps.
 3. A circuit substrate of a multiple layer according to claim 1, wherein the wiring pattern is a wiring pattern having a land to which the external connection terminal is joined on the other end side of the bump.
 4. A circuit substrate of a multiple layer according to claim 1, wherein tips of the bumps are protruded from a single surface of the insulating adhesive agent layer.
 5. A semiconductor device characterized in that: a circuit substrate comprised of multiple layers, where a layer is provided in such a manner that bumps, which are electrically connected to connection electrodes provided on one face of a surface mount device which is a semiconductor chip or a chip size package and to metal foil wiring patterns, are arranged in the same arrangement as that of said connection electrodes and protrude onto a first side of the sheet of metal foil; said wiring patterns, which are electrically connected to said bumps with each other, being formed on said one side of the sheet of metal foil; external connection terminals are protruded onto a second side of said sheet of metal foil; and an insulating adhesive agent layer is made to adhere onto said one side of the sheet of metal foil, wherein the circuit substrate is made to adhere onto said one face of the surface mount device by said insulating adhesive agent layer; and tips of the bumps respectively come into contact with the connection electrodes and said wiring patterns.
 6. A semiconductor device according to claim 5, wherein the wiring pattern is an island-shaped wiring pattern having a land to which the external connection terminal is joined at a base portion of the bump.
 7. A semiconductor device according to claim 5, wherein the wiring pattern is a wiring pattern having a land to which the external connection terminal is joined on the other end side of the bump.
 8. A semiconductor device according to claim 5, wherein the external connection terminals are joined to the lands.
 9. A semiconductor device characterized in that: a circuit substrate of multiple layers which are composed in such a manner that bumps, which are electrically connected to connection electrodes provided on one face of a surface mount device which is a semiconductor chip or chip size package, are arranged in the same plane arrangement as that of said connection electrodes and protruded onto one side of a sheet of metal foil; said sheet of metal foil on which wiring patterns are formed for electrically connecting said bumps to external connection terminals with each other; external connection terminals which respectively correspond to the bumps and are protruded onto the other side of the sheet of metal foil; and an insulating adhesive agent layer is made to adhere onto said one face of the sheet of metal foil having bumps, is made to adhere onto said one face of the surface mount device by said insulating adhesive agent layer; and tips of the bumps respectively come into contact with the connection electrodes.
 10. A semiconductor device according to claim 9, wherein the outside of the external connection terminals are plated with solder.
 11. A semiconductor device according to claim 9, wherein the external connection terminals are made of conductive material different from that of the sheet of metal foil.
 12. A semiconductor device according to claim 9, wherein the pointed end portion of the outside of the external connection terminals is formed flat.
 13. A circuit substrate composed of a plurality of layers and including: a first layer comprising a first wiring pattern foil with a plurality of bumps, said bumps which are electrically connected to connection electrodes provided on one face of a surface mount device which is a semiconductor chip or chip size package, and which are arranged in the same plane as that of said connection electrodes, wherein the bumps protrude from one side of a sheet of metal foil which form the first wiring pattern and are electrically connected to the first wiring pattern; and an insulating adhesive agent layer adapted to adhere onto one face of said metal foil having bumps; and at least one additional layer which comprises a second wiring pattern foil with a plurality of bumps, said bumps which are electrically connected to the first wiring pattern, and which are arranged in the same plane as that of said first wiring pattern, wherein the bumps protrude onto one side of the sheet of metal foil which form the second wiring pattern, and are electrically connected to the second wiring pattern; and an insulating adhesive agent layer adapted to adhere onto one face of said metal foil having bumps.
 14. The circuit substrate of claim 13, wherein the wiring pattern which is not the first wiring pattern is an island-shaped wiring pattern having a land to which an external connection terminal is joined at a base portion of the bumps.
 15. The circuit substrate of claim 14, wherein the external connection terminals are made of conductive material different from that of the sheet of metal foil.
 16. The circuit substrate of claim 15, wherein the conductive material is made of conductive paste.
 17. The circuit substrate of claim 13, wherein a wiring pattern which is not the first wiring pattern is a wiring pattern having a land to which the external connection terminal is joined on the other end side of the bump.
 18. The circuit substrate of claim 13, wherein tips of the bumps protrude from a surface of the insulating adhesive agent layer.
 19. The circuit substrate of claim 13, further comprising a power supply layer.
 20. The circuit substrate of claim 13, further comprising a ground.
 21. The circuit substrate of claim 13, further comprising external connection terminals protruding from a second side from said foil wiring patterns. 